Hold-down means for a shear machine or the like



Oct l0 1967 E. w. PEARsoN HOLD-DOWN MEANS FOR A vSIIEAR MACHINE OR THE LIKE 2 Sheets-Sheet 1 Filed June 8, 1964 Vlo H/.S ATTORNEYS HOLD-DOWN MEANS FOR A SHEAR'MAGHINE 0R THE LIKE Filed VJune 8, 1964 oct. 1o, 1967 E. wpsAsQN 2 Sheets-Sheet 2 INVENTOR EUGENE W. PES/V HAS` ATTORNEYS United States Patent O 3,345,897 HOLD-DWN MEANS FOR A SHEAR MACHINE Y OR THE LIKE Eugene W. Pearson, Orinda, Calif., assignor to Pacific Press & Shear Corp., a corporation of Illinois Filed June 8, 1964, Ser. No. 373,152 7 Claims. (Cl. 83-389) My invention relates to shear machines and the like, and more particularly to hold-down means for immobilizing Work in such machines while being operated on.

Conventional hold-down means, whether mechanically or Vhydraulically operated, involve a plurality of equally spaced work engaging hold-down rods, which, because of the high unit loadings involved in their use, are made of steel, and in many cases, at their Work contacting ends or feet, are also hardened to minimize wear.

As a result, not only will these hold-downs create sub- Stantial noise when brought into engagement with the work or the work supporting table, but, what is even of more importance, they can very readily mar the surface of the work. This cannot be tolerated on many fairly soft materials such as aluminum, nor fairly hard materials such as stainless steel where a high polish requirement may be in order.

Efforts to minimize the noise problem, as well as the problem of marring the work, have been along the lines of providing such work engaging rods with rubber or leather cups. This, however, is-found not to be the complete answer, for not only can highly polished surfaces still be marked up, but the use of such cups introduces a new problem, namely that of replacing them frequently, due to the short life expectancy thereof.

Among the objects of my invention are:

(l) To provide novel and improved hold-down means for a shear or like machine.

(2) To provide novel and improved hold-down means for a shear or like machine, which will not mar work exposed to the hold-down pressures thereof.

(3) I-"o provide novel and improved hold-down means which will be noiseless in operation.

(4) To provide novel and improved hold-down means which shall eliminate points of high localized pressure concentration on the work. Y

(5) To provide novel land improved hold-down means which Will function efficiently in clamping work which spans but a limited portion of the work table.

Additional objects of my invention will be brought out in the following description of a preferred embodiment of the same, taken in conjunction with the accompanying drawings wherein:

FIGURE l is a fragmentary front view in elevation of a shear, depicting one form of the present invention;

FIGURE 2 is a view in section taken in the plane 2-2 of FIGURE 1;Y Y 1 FIGURE 3 is a fragmentary View in section, illustrating a somewhat different form of the invention from that depicted in FIGURE 1;

FIGURE 4 is a view corresponding to that of FIGURE 3, but depicting the hold-down means in operation;

FIGURE 5 is a fragmentary view in section illustrating a variation inthe manner of alfixing the hold-down tube to the back-up member; y v

` FIGURE v6 is aview corresponding to that of FIGURE 3,345,897 Patented Oct. 10, 1967 5, but depicting adifferent manner of axing the holddown tube to the back-up member.

Referring to the drawings for details of my invention in its preferred form, the hold-down means 1 is for use in a shear machine or the like, normally comprising a table 3 for supporting work 5 to be operated on, and if the machine is a vshear machine, the work supporting table will support along its far or rear edge, a lower or fixed knife 7.

A ram 9 which is conventionally slid-ably supported on ways carried by the end walls or end housings 11 of the machine frame, and driven by hydraulic motors 12 carries an upper shear knife 13 in slicing relationship to the lower liXed knife 7.

The hold-down means of the present invention broadly includes a back-up member 15 extending across the table to the front of the ram, and substantially parallel to the surface of the table. The back-up member, in this embodiment, is 4rigidiiied by a continuous stifener plate 16. Along the lower edge of the back-up member, is a hollow tube 17 of flexible material, preferably closed at both ends and provided with a filling tube 19 coupled thereto at an intermediate point, preferably midway of the closed ends.

The back-up member 15 may be fxedly supported between the hydraulic motors, of the machine, in which case, the hold-down tube 17 will be inflatable to alter the distance between the tube and the work table, whereby to impart pressure to work disposed on the table below the hold-down means, and clamp such work in preparation for a shearing thereof.

In lieu of fixedly mounting the back-up member between the hydraulic motors of the machine, the back-up member may be slidably or reciprocally mounted for downward movement to clamp the work in advance of the shearing thereof. Either the back-up member may be slidably mounted on its own ways and operated to move in advance of the upper knife, or it may be affixed to the ram of the machine with the hold-down tube carried thereby in advance of the upper knife to effect prior engagement with the work.

In the latter case, the back-up member 15, at spaced points therealong, includes upright rods 23, preferably threaded at -theirupper ends to receive supporting nuts 25, whereby the back-up member may be supported from the ram, by running the rods through suitably spaced ram brackets 27 before aflixing the nuts thereto.

A compression'spring 29 about each rod, between its associated bracket and the back-up member, normally urges the back-up member to the lowest position permitted 'by the nut 25, which lowest position is such Ias to leave adequate space for insertion of work beneath the clamping tube. Upon descent of the ram, the clamping tube will engage and clamp the work in advance of the upper shearing knife. v

Where the back-up member is reciprocally operated, as in the embodiment of FIGURES 3 ,and 4, the hold-down tube may be permanently inflated, for in this embodiment, release of the hold-down means from pressure engagement with the work -is accomplished by retraction of `the backup member 15, as distinguished from the act of deflating the hold-down tubein the first embodiment of the invention.

.Any resilient or equivalent means.capable of being utilized in lieu of the spring 29 to perform its function,

may be employed, and such may include hydraulically or pneumatically controlled pistons.

Also, inasmuch as the hold-down tube may be permanently inflated in the embodiment of FIGURES 3 and 4, any solid strip of resilient material such as rubber, known forms of resilient plastic, and the like may be utilized in lieu of a tube as a cushion strip in this embodiment.

Various modes of attaching of the hold-down tube to the back-up member may be availed of. In the embodiment of FIGURES l and 2, the hold-down tube is affixed as by means of some adhesive or binding agent. For this purpose, the tube may be extruded of flexible material such as rubber or resilient plastic or the like, with a flanged longitudinal base 33 having a flattened or planar surface substantially matching that of the back-up member.

Alternatively, the hold-down tube with such base 33 may be assembled to the vback-up member by the use of suitable retaining clips 35 of essentially L shape, which are screwed to the back-up member in engagement with the flanged base. This latter mode of application of the hold-down tube `removably secures the same in functional position, and thus permits convenient removal thereof for servicing or replacement if such be necessary.

In lieu of the foregoing, the back-up member may be formed of channel beam inverted to provide down flanges 37 between which to receive the hold-down tube, which, in this instance, may be of conventional section, and will have sufficient surface area in contact with the proximate surfaces of the channel to permit of its being adhesively secured or otherwise bonded thereto. The hold-down tube being partially confined within the channel, any inflation of the tube will cause the same to expand predominantly in the downward direction, or in other words, in the direction of desired clamping pressure against the work. In this embodiment, the inflating tube may be brought out through a suitably located hole in the channel, or if the tube be of the permanently inflated type, it will extend sufficiently below the flanges to preclude the flanges from striking the work.

From the foregoing description of my invention, it will be apparent that the same fulfills all the objects attributed thereto, and while I have illustrated and described the same in considerable detail, I do not desire to be limited in my protection to the specific details illustrated and described except as may be necessitated by the appended claims.

I claim:

1. In a shear or like machine, having a tool carrying ram for performing an operation on work,

a work supporting table for holding work to be operated on,

a `back-up member extending across said table, substantially parallel to but out of the plane of said ram,

a cushion strip,

means supporting said cushion strip along said back-up member,

and means for altering the distance between said cushion strip and said table to engage such work and resist lateral drag thereon as said tool carrying ram performs an operation on such work.

2. In a shear or like rrnachine, having a tool carrying ram for performing an operation on work,

a work supporting table for holding work to be operated on,

a back-up member extending across said table, substantially parallel to but out of the plane of said ram, and having a lower edge substantially parallel to said table,

a cushion strip,

means supporting said cushion strip along the lower edge of said back-up member,

and means for altering the distance between said cushion strip and said table to engage such work and resist lateral drag thereon as said tool carrying ram performs an operation on such work.

3. In a shear or like machine, having a tool carrying ram for performing an operation on work,

a work supporting table for holding work to-be operated on,

a back-up member extending across said table, substantially parallel to but out of the plane of said ram, and substantially parallel to said table,

a hollow tube of flexible material,

means supporting said hollow tube along the lower edge of said back-up member, between the back-up member and said table,

and means for altering the distance between said tube and said table to engage such work and resist lateral drag thereon as said tool carrying ram performs an operation on such work.

4. In a shear or like machine, having a tool carrying ram for performing an operation on work,

a work supporting table for holding work to be operated on,

a rigid back-up member extending across said table, substantially parallel to but out of the plane of said ram,

a hollow tube of flexible material,

means supporting said hollow tube along the lower edge of said back-up member,

and means for intiating said hollow tube to alter the distance between said tube and said table to engage such work and resist lateral drag thereon as said tool carrying ram performs an operation on such work.

5. In a shear or like machine, having a tool carrying ram for performing an oper-ation on work,

a work supporting table for holding work to be operated on,

a rigid immovable back-up member extending across said table, substantially parallel t-o but out of the plane of said ram,

a hollow tube of flexible material,

means supporting said hollow tube along the lower edge of said back-up member,

and means for inilating said hollow tube to alter the distance between said tube land said table to engage such work and resist lateral drag thereon as said tool carrying ram performs an operation on such work.

6. In a shear or like machine, having .a tool carrying ram for performing an operation on work,

a work supporting table for holding work to be operated on,

a rigid back-up member extending across said table, substantially parallel to but out of the plane of said ram, and having its lower edge substantially parallel to said table,

a hollow tube of flexible material,

means supporting said hollow tube along the lower I edge of said back-up member,

and means for adjusting the position of said back-up member with respect t0 said table to alter the distance between said tube and said table to engage such work and resist lateral drag thereon as said tool carrying ram performs an operation on such work.

7. In a shear or like machine, having a tool carrying ram for performing an operation on work,

a work supporting table for holding work to be operated on,

a rigid back-up member extending across said table, substantially parallel to but out of the plane of said rami, and having its lower edge substantially parallel lto said table,

a hollow tube of flexible material,

means supporting said hollow tube along the lower edge of said back-up member, between said back-up member and said work table,

and means for inflating said hollow tube to alter the distance between said tube and said table to engage such Work Iand resist lateral dragthereonlas said tool carrying ram performs an operation on such work.

References Cited UNITED STATES PATENTS 6 1/ 1954 Hasselquist 269-22 5/1962 Pater 83--461 8/ 1962 Thumin. 9/1962 Pearson 83-390 FOREIGN PATENTS 2/ 1948 Great Britain.

HAROLD D. WHITEHEAD, Primary Examiner. 

1. IN A SHEAR OR LIKE MACHINE, HAVING A TOOL CARRYING RAM FOR PERFORMING AN OPERATION ON WORK, A WORK SUPPORTING TABLE FOR HOLDING WORK TO BE OPERATED ON, A BACK-UP MEMBER EXTENDING ACROSS SAID TABLE, SUBSTANTIALLY PARALLEL TO BUT OUT OF THE PLANE OF SAID RAM, A CUSHION STRIP, MEANS SUPPORTING SAID CUSHION STRIP ALONG SAID BACK-UP MEMBER, AND MEANS FOR ALTERING THE DISTANCE BETWEEN SAID CUSHION STRIP AND SAID TABLE TO ENGAGE SUCH WORK AND RESIST LATERAL DRAG THEREON AS SAID TOOL CARRYING RAM PERFORMS AN OPERATION ON SUCH WORK. 